“I write to urge you to direct your staff to discontinue the practice of (1) forcing Tribal Nations that have Self-Governance agreements with DOI to enter into a Memorandum of Understanding (MOU) with the Appraisal and Valuation Services Office (AVSO) and, (2) requiring language that references the MOU in their Funding Agreements and/or Compacts as a condition of being able to compact real estate appraisal services.”